MS Teams & Mattermost: Scaling to 25k Users

We are preparing to launch the MS Teams Plugin, synchronizing chats, DMs and GMs for up to 25k users spread across MS Teams and Mattermost. Scaling up to this many users has risks!

  • Can we scale past the per-organization limit of 10,000 total subscriptions and adopt per-user chat subscriptions against the MS Graph API? Or should we stick with the global chats subscription even if we don’t /need/ all the events?

  • Are we likely to run up against rate limiting that fundamentally constrains the timeliness of synchronizing chats? What other unknowns should we evaluate when interfacing with the MS Graph API at that scale?

(Note that this post is a focused version of the details outlined in